BM31

Synopsis

BM31 is part of the Swiss-Norwegian beamlines along of BM01. It specialises in combining X-ray absorption spectroscopy (XAS), X-ray diffraction (XRD) and X-ray total-scattering (XRTS) with the newly installed (2022) endstation. The optics and end-station can automatically switch between various configurations. This enables measurements of XAS, XRD, and XRTS datasets in a combined time-resolved manner on the same sample under the same experimental conditions.

A set of sample environments is available for temperature-dependent-, catalytic- and electrochemistry experiments as well as a gas distribution and analysis system.

Status: open

Disciplines

Physics
Materials and Engineering
Chemistry

Techniques

XAS - X-ray Absorption Spectroscopy
XRD - X-ray Diffraction
PDF - Pair Distribution Function

Energy range

4.9 - 48.0 keV

Beam size

Minimum (H x V) : 50.0 x 50.0 µm²
Maximum (H x V) : 10.0 x 1.0 mm²

Sample environments

Gas flow stage with furnace for catalytic experiments in capillaries. Tmax 900 °C. High heating rate (100 °C/min), and low axial gradient capillary furnace. Gas distribution system including 4 mass flow controllers, each with a switch valve, 2 back pressure regulators (sample and exhaust), and a mass spectrometer. MFCs, switch valves and BPRs controllable from Pylaus software to synchronise with measurements.
Static-gas pressure using a rig with turbo vacuum pump and gas dosing.
Electrochemistry experiments can be performed with a BioLogic 16-channel potentiostat.
Oxford Cryosystems Cryostream for 100 - 500 K (liquid N2).
IUCR goniometer mount with goniometer heads for capillary measurements (XRD, PDF, XAS).
Capillary rack with a fast x-, y-, z- stage for running multiple ex-situ samples in (XRD, PDF, XAS).
Pellet grid for multiple ex-situ pellets (XAS).

Detectors

14 ion chambers on translation stages - 4 I0 (before sample), 6 I1 (after sample) and 4 I2 (after I1) chambers available, selected automatically based on the measurement energy - moving during experiment to match energy
A Vortex SDD with XIA Falcon X fast digital multichannel analyzer electronics for fluorescence spectroscopy
A PILATUS3 X CdTe 2M with x-, y- and z- translation and pitch rotation for XRD and PDF. Sample-to-detector distance 190 - 1160 mm, pitch rotation up to 15°. Qmax 27 Å-1.

Technical details

XAS - unfocused 4.9 - 45 keV

XRD - focused 48 keV

XRTS/PDF - focused 48 keV

Resonant XRD, thin film XRD - unfocused 15-45 keV

Optics

Element	Description
Monochromator	Air-bearing liquid nitrogen double-crystal monochromator
Monochromator crystals	2 Flat Si[111] pair, and 2 sagittal focusing second crystals
Spectral range	4.8 - 45 keV for XAS (unfocused), ~40 and ~50keV focused for XRD & PDF
Intrinsic resolution (DE/E)	Si[111]: 1.4 x 10-4
Spot size	up to 10mm H x 0.6mm V and focussed 50µm H x 300µm V